Radiology of Severe Acute Respiratory Syndrome (SARS)

Circulating calprotectin levels four months after severe and non-severe COVID-19

BACKGROUND

Calprotectin is an inflammatory marker mainly released by activated neutrophils that is increased in acute severe COVID-19. After initial recovery, some patients have persistent respiratory impairment with reduced diffusion capacity of the lungs for carbon monoxide (DLCO) months after infection. Underlying causes of this persistent impairment are unclear. We aimed to investigate the correlation between circulating calprotectin, persistent lung functional impairment and intensive care unit (ICU) stay after COVID-19 in two university hospital centres in Switzerland.

METHODS

Calprotectin levels were measured in serum from 124 patients (50% male) from the Bern cohort (post-ICU and non-ICU patients) and 68 (76% male) from the Lausanne cohort (only post-ICU patients) four months after COVID-19. Calprotectin was correlated with clinical parameters. Multivariate linear regression (MLR) was performed to evaluate the independent association of calprotectin in different models.

RESULTS

Overall, we found that post-ICU patients, compared to non-ICU, were significantly older (age 59.4 ± 13.6 (Bern), 60.5 ± 12.0 (Lausanne) vs. 48.8 ± 13.4 years) and more obese (BMI 28.6 ± 4.5 and 29.1 ± 5.3 vs. 25.2 ± 6.0 kg/m2, respectively). 48% of patients from Lausanne and 44% of the post-ICU Bern cohort had arterial hypertension as a pre-existing comorbidity vs. only 10% in non-ICU patients. Four months after COVID-19 infection, DLCO was lower in post-ICU patients (75.96 ± 19.05% predicted Bern, 71.11 ± 18.50% Lausanne) compared to non-ICU (97.79 ± 21.70% predicted, p < 0.01). The post-ICU cohort in Lausanne had similar calprotectin levels when compared to the cohort in Bern (Bern 2.74 ± 1.15 µg/ml, Lausanne 2.49 ± 1.13 µg/ml vs. non-ICU 1.86 ± 1.02 µg/ml; p-value < 0.01). Calprotectin correlated negatively with DLCO (r= -0.290, p < 0.001) and the forced vital capacity (FVC) (r= -0.311, p < 0.001).

CONCLUSIONS

Serum calprotectin is elevated in post-ICU patients in two independent cohorts and higher compared to non-ICU patients four months after COVID-19. In addition, there is a negative correlation between calprotectin levels and DLCO or FVC. The relationship between inflammation and lung functional impairment needs further investigations.

TRIAL REGISTRATION

NCT04581135.

Chest CT Findings after Mild COVID-19 Do Not Explain Persisting Respiratory Symptoms: An Explanatory Study

(1) Background: Lung tissue involvement is frequently observed in acute COVID-19. However, it is unclear whether CT findings at follow-up are associated with persisting respiratory symptoms after initial mild or moderate infection. (2) Methods: Chest CTs of patients with persisting respiratory symptoms referred to the post-COVID-19 outpatient clinic were reassessed for parenchymal changes, and their potential association was evaluated. (3) Results: A total of 53 patients (31 female) with a mean (SD) age of 46 (13) years were included, of whom 89% had mild COVID-19. Median (quartiles) time from infection to CT was 139 (86, 189) days. Respiratory symptoms were dyspnea (79%), cough (42%), and thoracic pain (64%). Furthermore, 30 of 53 CTs showed very discrete and two CTs showed medium parenchymal abnormalities. No severe findings were observed. Mosaic attenuation (40%), ground glass opacity (2%), and fibrotic-like changes (25%) were recorded. No evidence for an association between persisting respiratory symptoms and chest CT findings was found. (4) Conclusions: More than half of the patients with initially mild or moderate infection showed findings on chest CT at follow-up. Respiratory symptoms, however, were not related to any chest CT finding. We, therefore, do not suggest routine chest CT follow-up in this patient group if no other indications are given.

A compact CNN model for automated detection of COVID-19 using thorax x-ray images

COVID-19 is an epidemic, causing an enormous death toll. The mutational changing of an RNA virus is causing diagnostic complexities. RT-PCR and Rapid Tests are used for the diagnosis, but unfortunately, these methods are ineffective in diagnosing all strains of COVID-19. There is an utmost need to develop a diagnostic procedure for timely identification. In the proposed work, we come up with a lightweight algorithm based on deep learning to develop a rapid detection system for COVID-19 with thorax chest x-ray (CXR) images. This research aims to develop a fine-tuned convolutional neural network (CNN) model using improved EfficientNetB5. Design is based on compound scaling and trained on the best possible feature extraction algorithm. The low convergence rate of the proposed work can be easily deployed into limited computational resources. It will be helpful for the rapid triaging of victims. 2-fold cross-validation further improves the performance. The algorithm proposed is trained, validated, and testing is performed in the form of internal and external validation on a self-collected and compiled a real-time dataset of CXR. The training dataset is relatively extensive compared to the existing ones. The performance of the proposed technique is measured, validated, and compared with other state-of-the-art pre-trained models. The proposed methodology gives remarkable accuracy (99.5%) and recall (99.5%) for biclassification. The external validation using two different test dataset also give exceptional predictions. The visual depiction of predictions is represented by Grad-CAM maps, presenting the extracted features of the predicted results.

Long-term respiratory follow-up of ICU hospitalized COVID-19 patients: Prospective cohort study

BACKGROUND

Coronavirus disease (COVID-19) survivors exhibit multisystemic alterations after hospitalization. Little is known about long-term imaging and pulmonary function of hospitalized patients intensive care unit (ICU) who survive COVID-19. We aimed to investigate long-term consequences of COVID-19 on the respiratory system of patients discharged from hospital ICU and identify risk factors associated with chest computed tomography (CT) lesion severity.

METHODS

A prospective cohort study of COVID-19 patients admitted to a tertiary hospital ICU in Brazil (March-August/2020), and followed-up six-twelve months after hospital admission. Initial assessment included: modified Medical Research Council dyspnea scale, SpO2 evaluation, forced vital capacity, and chest X-Ray. Patients with alterations in at least one of these examinations were eligible for CT and pulmonary function tests (PFTs) approximately 16 months after hospital admission. Primary outcome: CT lesion severity (fibrotic-like or non-fibrotic-like). Baseline clinical variables were used to build a machine learning model (ML) to predict the severity of CT lesion.

RESULTS

In total, 326 patients (72%) were eligible for CT and PFTs. COVID-19 CT lesions were identified in 81.8% of patients, and half of them showed mild restrictive lung impairment and impaired lung diffusion capacity. Patients with COVID-19 CT findings were stratified into two categories of lesion severity: non-fibrotic-like (50.8%-ground-glass opacities/reticulations) and fibrotic-like (49.2%-traction bronchiectasis/architectural distortion). No association between CT feature severity and altered lung diffusion or functional restrictive/obstructive patterns was found. The ML detected that male sex, ICU and invasive mechanic ventilation (IMV) period, tracheostomy and vasoactive drug need during hospitalization were predictors of CT lesion severity(sensitivity,0.78±0.02;specificity,0.79±0.01;F1-score,0.78±0.02;positive predictive rate,0.78±0.02; accuracy,0.78±0.02; and area under the curve,0.83±0.01).

CONCLUSION

ICU hospitalization due to COVID-19 led to respiratory system alterations six-twelve months after hospital admission. Male sex and critical disease acute phase, characterized by a longer ICU and IMV period, and need for tracheostomy and vasoactive drugs, were risk factors for severe CT lesions six-twelve months after hospital admission.

Lung transplantation in patients with lung disease secondary to coronavirus disease 2019 infection

PURPOSE OF REVIEW

In this article, we describe preoperative patient selection and outcomes of patients with lung disease secondary to infection from COVID-19 who receive lung transplantation.

RECENT FINDINGS

Lung transplants for patients with lung disease secondary to infection from COVID-19 have been performed successfully in over 200 patients in the United States. The preoperative course of these patients is somewhat atypical in comparison with patients who have had lung transplants related to chronic lung diseases, where there are more traditional indications for lung transplants. COVID-19 patients have more severe pulmonary disease often requiring mechanical ventilation and extracorporeal mechanical ventilation (ECMO), frequent nosocomial infections, and renal and cardiac dysfunction. The intraoperative course of these COVID-19 patients is often longer and requires increased transfusions of blood products in comparison with non-COVID-19 patients. Additionally, in the postoperative period, COVID-19 patients more frequently require mechanical ventilation and ECMO support. However, the survival rate of such patients at 6 months is greater than 90%.

SUMMARY

Patients with respiratory failure secondary to COVID-19 infection that require a lung transplant generally have a complicated preoperative course and the operations are more complex, but the long-term outcomes are excellent.

Long-term Lung Abnormalities Associated with COVID-19 Pneumonia

In the 3rd year of the SARS-CoV-2 pandemic, much has been learned about the long-term effects of COVID-19 pneumonia on the lungs. Approximately one-third of patients with moderate-to-severe pneumonia, especially those requiring intensive care therapy or mechanical ventilation, have residual abnormalities at chest CT 1 year after presentation. Abnormalities range from parenchymal bands to bronchial dilation to frank fibrosis. Less is known about the long-term pulmonary vascular sequelae, but there appears to be a persistent, increased risk of venothromboembolic events in a small cohort of patients. Finally, the associated histologic abnormalities resulting from SARS-CoV-2 infection are similar to those seen in patients with other causes of acute lung injury.

Quantitative inspiratory-expiratory chest CT findings in COVID-19 survivors at the 6-month follow-up

We evaluated pulmonary sequelae in COVID-19 survivors by quantitative inspiratory-expiratory chest CT (QCT) and explored abnormal pulmonary diffusion risk factors at the 6-month follow-up. This retrospective study enrolled 205 COVID-19 survivors with baseline CT data and QCT scans at 6-month follow-up. Patients without follow-up pulmonary function tests were excluded. All subjects were divided into group 1 (carbon monoxide diffusion capacity [DL_CO] < 80% predicted, n = 88) and group 2 (DL_CO ≥ 80% predicted, n = 117). Clinical characteristics and lung radiological changes were recorded. Semiquantitative total CT score (0-25) was calculated by adding five lobes scores (0-5) according to the range of lesion involvement (0: no involvement; 1: < 5%; 2: 5-25%; 3: 26-50%; 4: 51-75%; 5: > 75%). Data was analyzed by two-sample t-test, Spearman test, etc. 29% survivors showed air trapping by follow-up QCT. Semiquantitative CT score and QCT parameter of air trapping in group 1 were significantly greater than group 2 (p < 0.001). Decreased DL_CO was negatively correlated with the follow-up CT score for ground-glass opacity (r = - 0.246, p = 0.003), reticulation (r = - 0.206, p = 0.002), air trapping (r = - 0.220, p = 0.002) and relative lung volume changes (r = - 0.265, p = 0.001). COVID-19 survivors with lung diffusion deficits at 6-month follow-up tended to develop air trapping, possibly due to small-airway impairment.

Long-term outcomes and recovery of patients who survived COVID-19: LUNG INJURY COVID-19 Study

Background

LUNG INJURY COVID-19 (clinicaltrials.gov NCT 21/399-E) is a registry-based prospective observational cohort study to evaluate long-term outcomes and recovery 12 months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection according to severity.

Methods

Three hundred five coronavirus disease 2019 (COVID-19) survivors were included (moderate, 162; severe, 143). Twelve months after SARS-CoV-2 infection, there was resolution of respiratory symptoms (37.9% in severe vs 27.3% in moderate pneumonia; P = .089).

Results

Exertional dyspnea was present (20% in severe vs 18.4% in moderate; P = .810). Abnormalities on chest radiology imaging were detected more often in severe COVID-19 infection vs moderate infection (29% vs 8.8%; P < .001). Pulmonary function testing (forced spirometry or diffusion) performed at 12 months of mean follow-up according to protocol detected anomalies in 31.4% of patients with severe COVID-19 courses and in 27.7% of moderate patients. Risk factors associated with diffusion impairment at 12 months were age (odds ratio [OR], 1.05; 95% CI, 1.01–1.10; P = .008), forced expiratory volume in 1 second predicted at follow-up (OR, 0.96; 95% CI, 0.93–0.99; P = .017), and dyspnea score at follow-up (OR, 3.16; 95% CI, 1.43–6.97; P = .004). Computed tomography (CT) scans performed at 12 months of mean follow-up showed evidence of fibrosis in almost half of patients with severe COVID-19 courses, who underwent CT according to protocol.

Conclusions

At 12 months from infection onset, most patients refer to symptoms, particularly muscle weakness and dyspnea, and almost one-third of patients with severe COVID-19 pneumonia had impaired pulmonary diffusion and abnormalities on chest radiology imaging. These results emphasize the importance of systematic follow-up after severe COVID-19, with appropriate management of pulmonary sequelae.

Lung Ultrasound as a First-Line Test in the Evaluation of Post-COVID-19 Pulmonary Sequelae

Background: Interstitial lung sequelae are increasingly being reported in survivors of COVID-19 pneumonia. An early detection of these lesions may help prevent the development of irreversible lung fibrosis. Lung ultrasound (LUS) has shown high diagnostic accuracy in interstitial lung disease (ILD) and could likely be used as a first-line test for post-COVID-19 lung sequelae. Methods: Single-center observational prospective study. Follow-up assessments of consecutive patients hospitalized for COVID-19 pneumonia were conducted 2-5 months after the hospitalization. All patients underwent pulmonary function tests (PFTs), high-resolution computed tomography (HRCT), and LUS. Radiological alterations in HRCT were quantified using the Warrick score. The LUS score was obtained by evaluating the presence of pathological B-lines in 12 thoracic areas (range, 0-12). The correlation between the LUS and Warrick scores was analyzed. Results: Three hundred and fifty-two patients who recovered from COVID-19 pneumonia were recruited between July and September 2020. At follow-up, dyspnea was the most frequent symptom (69.3%). FVC and DLCO alterations were present in 79 (22.4%) and 234 (66.5%) patients, respectively. HRCT showed relevant interstitial lung sequelae (RILS) in 154 (43.8%) patients (Warrick score ≥ 7). The LUS score was strongly correlated with the HRCT Warrick score (r = 0.77) and showed a moderate inverse correlation with DLCO (r = -0.55). The ROC curve analysis revealed that a LUS score ≥ 3 indicated an excellent ability to discriminate patients with RILS (sensitivity, 94.2%; specificity, 81.8%; negative predictive value, 94.7%). Conclusions: LUS could be implemented as a first-line procedure in the evaluation of Post-COVID-19 interstitial lung sequelae. A normal LUS examination rules out the presence of these sequelae in COVID-19 survivors, avoiding the need for additional diagnostic tests such as HRCT.

CT of Post-Acute Lung Complications of COVID-19

The acute course of COVID-19 is variable and ranges from asymptomatic infection to fulminant respiratory failure. Patients recovering from COVID-19 can have persistent symptoms and CT abnormalities of variable severity. At 3 months after acute infection, a subset of patients will have CT abnormalities that include ground-glass opacity (GGO) and subpleural bands with concomitant pulmonary function abnormalities. At 6 months after acute infection, some patients have persistent CT changes to include the resolution of GGOs seen in the early recovery phase and the persistence or development of changes suggestive of fibrosis, such as reticulation with or without parenchymal distortion. The etiology of lung disease after COVID-19 may be a sequela of prolonged mechanical ventilation, COVID-19-induced acute respiratory distress syndrome (ARDS), or direct injury from the virus. Predictors of lung disease after COVID-19 include need for intensive care unit admission, mechanical ventilation, higher inflammatory markers, longer hospital stay, and a diagnosis of ARDS. Treatments of lung disease after COVID-19 are being investigated, including the potential of antifibrotic agents for prevention of lung fibrosis after COVID-19. Future research is needed to determine the long-term persistence of lung disease after COVID-19, its impact on patients, and methods to either prevent or treat it. © RSNA, 2021.

Pulmonary Cystic Disease Associated With COVID 19 Pneumonia: An Emerging Atypical Manifestation

Chest tomography has played an essential role during the coronavirus disease 2019 (COVID-19) pandemic since it has allowed to suspect and diagnose the disease early and to assess the severity of lung involvement, predict the disease's course, and detect the complications associated with it. Certain chest CT findings have been reported in more than 70% of reverse transcription polymerase chain reaction (RT-PCR) test-proven COVID-19 cases, including ground-glass opacities, vascular enlargement, bilateral abnormalities, lower lobe involvement, and posterior predilection. In COVID-19-endemic regions, observing these chest CT findings should raise the suspicion of a possible COVID-19 diagnosis. Rare reported CT findings in RT-PCR test-proven COVID-19 cases include pleural effusion, lymphadenopathy, tree-in-bud sign, central lesion distribution, pericardial effusion, and cavitating lung lesions. The observation of one or more of these findings suggests an alternative diagnosis, although COVID-19 cannot be excluded from the differential diagnosis. Here, we report an interesting case of a patient with no relevant history presenting a COVID-19 infection which, as a complication, presented cystic lesions; we discuss its etiology briefly.

Preliminary Evidence for IL-10-Induced ACE2 mRNA Expression in Lung-Derived and Endothelial Cells: Implications for SARS-Cov-2 ARDS Pathogenesis

Angiotensin-converting enzyme 2 (ACE2) is a receptor for the spike protein of SARS-COV-2 that allows viral binding and entry and is expressed on the surface of several pulmonary and non-pulmonary cell types, with induction of a “cytokine storm” upon binding. Other cell types present the receptor and can be infected, including cardiac, renal, intestinal, and endothelial cells. High ACE2 levels protect from inflammation. Despite the relevance of ACE2 levels in COVID-19 pathogenesis, experimental studies to comprehensively address the question of ACE2 regulations are still limited. A relevant observation from the clinic is that, besides the pro-inflammatory cytokines, such as IL-6 and IL-1β, the anti-inflammatory cytokine IL-10 is also elevated in worse prognosis patients. This could represent somehow a “danger signal”, an alarmin from the host organism, given the immuno-regulatory properties of the cytokine. Here, we investigated whether IL-10 could increase ACE2 expression in the lung-derived Calu-3 cell line. We provided preliminary evidence of ACE2 mRNA increase in cells of lung origin in vitro, following IL-10 treatment. Endothelial cell infection by SARS-COV-2 is associated with vasculitis, thromboembolism, and disseminated intravascular coagulation. We confirmed ACE2 expression enhancement by IL-10 treatment also on endothelial cells. The sartans (olmesartan and losartan) showed non-statistically significant ACE2 modulation in Calu-3 and endothelial cells, as compared to untreated control cells. We observed that the antidiabetic biguanide metformin, a putative anti-inflammatory agent, also upregulates ACE2 expression in Calu-3 and endothelial cells. We hypothesized that IL-10 could be a danger signal, and its elevation could possibly represent a feedback mechanism fighting inflammation. Although further confirmatory studies are required, inducing IL-10 upregulation could be clinically relevant in COVID-19-associated acute respiratory distress syndrome (ARDS) and vasculitis, by reinforcing ACE2 levels.

Covid-19 imaging: A narrative review

Background

The 2019 novel coronavirus disease (COVID-19) imaging data is dispersed in numerous publications. A cohesive literature review is to be assembled.

Objective

To summarize the existing literature on Covid-19 pneumonia imaging including precautionary measures for radiology departments, Chest CT's role in diagnosis and management, imaging findings of Covid-19 patients including children and pregnant women, artificial intelligence applications and practical recommendations.

Methods

A systematic literature search of PubMed/med line electronic databases.

Results

The radiology department's staff is on the front line of the novel coronavirus outbreak. Strict adherence to precautionary measures is the main defense against infection's spread. Although nucleic acid testing is Covid-19's pneumonia diagnosis gold standard; kits shortage and low sensitivity led to the implementation of the highly sensitive chest computed tomography amidst initial diagnostic tools. Initial Covid-19 CT features comprise bilateral, peripheral or posterior, multilobar ground-glass opacities, predominantly in the lower lobes. Consolidations superimposed on ground-glass opacifications are found in few cases, preponderantly in the elderly. In later disease stages, GGO transformation into multifocal consolidations, thickened interlobular and intralobular lines, crazy paving, traction bronchiectasis, pleural thickening, and subpleural bands are reported. Standardized CT reporting is recommended to guide radiologists. While lung ultrasound, pulmonary MRI, and PET CT are not Covid-19 pneumonia's first-line investigative diagnostic modalities, their characteristic findings and clinical value are outlined. Artificial intelligence's role in strengthening available imaging tools is discussed.

Conclusion

This review offers an exhaustive analysis of the current literature on imaging role and findings in COVID-19 pneumonia.

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Chest computed tomography is a highly sensitive Covid −19 pneumonia's diagnostic tool.

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Initial Covid-19 CT features are bilateral, multifocal, peripheral or posterior ground-glass opacities, mainly in the lower lobes.

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Multifocal consolidations, bronchiectasis, pleural thickening, and subpleural bands are late disease stages features.

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Standardized CT reporting is recommended to guide radiologists.

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Artificial intelligence could strengthen available imaging tools.

Chest CT Imaging Characteristics of COVID-19 Pneumonia in Surviving and Non-surviving Hospitalized Patients: A Retrospective Study in a Referral Center in Tehran, Iran

Background: Coronavirus disease 2019 (COVID-19) has several chest computed tomography (CT) characteristics, which are important for the early management of this disease, because viral detection via RT-PCR can be time-consuming, resulting in a delayed pneumonia diagnosis. The Radiological Society of North America (RSNA) proposed a reporting language for CT findings related to COVID-19 and defined four CT categories: typical, indeterminate, atypical, and negative. Objectives: To retrospectively evaluate the chest CT characteristics of patients with COVID-19 pneumonia. Patients and Methods: A total of 115 hospitalized laboratory-verified COVID-19 cases, underdoing chest CT scan, were included in this study from April 30 to May 15, 2020. Of 115 cases, 53 were discharged from the hospital, and 62 expired. The initial clinical features and chest CT scans were assessed for the type, pattern, distribution, and frequency of lesions. Moreover, the findings were compared between ward-hospitalized, intensive care unit (ICU)-admitted, and non-surviving (expired) patients. Results: Of four CT categories, typical CT findings for COVID-19 were more frequent in the expired group (77.4%), compared to the ward-admitted (44.8%) and ICU-admitted (70.8%) groups (P = 0.017). However, no significant difference was observed in the prevalence of intermediate or atypical CT findings between the groups. Negative CT scans for the diagnosis of COVID-19 were significantly fewer in the expired group (0%) as compared to the ward-admitted (10.3%) and ICU-admitted (8.3%) groups (P = 0.0180). Also, the mean number of involved lung lobes and segments was significantly higher in the expired group compared to the other two groups (P = 0.032 and 0.010, respectively). The right upper lobe involvement, right middle lobe involvement, bilateral involvement, central lesion, air bronchogram, and pleural effusion were among CT scan findings with a significantly higher prevalence in non-surviving cases (P < 0.0001, 0.047, 0.01, 0.036, 0.038, and 0.047, respectively). Conclusion: The increased number of involved lung lobes and segments, bilateral and central distribution patterns, air bronchogram, and severe pleural effusion in the initial chest CT scan can be related to the increased severity and poor prognosis of COVID-19.

An Overview of Deep Learning Techniques on Chest X-Ray and CT Scan Identification of COVID-19

Pneumonia is an infamous life-threatening lung bacterial or viral infection. The latest viral infection endangering the lives of many people worldwide is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19. This paper is aimed at detecting and differentiating viral pneumonia and COVID-19 disease using digital X-ray images. The current practices include tedious conventional processes that solely rely on the radiologist or medical consultant's technical expertise that are limited, time-consuming, inefficient, and outdated. The implementation is easily prone to human errors of being misdiagnosed. The development of deep learning and technology improvement allows medical scientists and researchers to venture into various neural networks and algorithms to develop applications, tools, and instruments that can further support medical radiologists. This paper presents an overview of deep learning techniques made in the chest radiography on COVID-19 and pneumonia cases.

COVID-19 pulmonary consolidations detection in chest X-ray using progressive resizing and transfer learning techniques

A viral outbreak with a lower respiratory tract febrile illness causes pulmonary syndrome named COVID-19. Pulmonary consolidations developed in the lungs of the patients are imperative factors during prognosis and diagnosis. Existing Deep Learning techniques demonstrate promising results in analyzing X-ray images when employed with Transfer Learning. However, Transfer Learning has its inherent limitations, which can be prevaricated by employing the Progressive Resizing technique. The Progressive Resizing technique reuses old computations while learning new ones in Convolution Neural Networks (CNN), enabling it to incorporate prior knowledge of the feature hierarchy. The proposed classification model can classify pulmonary consolidation into normal, pneumonia, and SARS-CoV-2 classes by analyzing X-rays images. The method exhibits substantial enhancement in classification results when the Transfer Learning technique is applied in consultation with the Progressive Resizing technique on EfficientNet CNN. The customized VGG-19 model attained benchmark scores in all evaluation criteria over the baseline VGG-19 model. GradCam based feature interpretation, coupled with X-ray visual analysis, facilitates improved assimilation of the scores. The model highlights its strength to assist medical experts in the COVID-19 identification during the prognosis and subsequently for diagnosis. Clinical implications exist in peripheral and remotely located health centers with the paucity of trained human resources to interpret radiological investigations' findings.

Human-Based Advanced in vitro Approaches to Investigate Lung Fibrosis and Pulmonary Effects of COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has caused considerable socio-economic burden, which fueled the development of treatment strategies and vaccines at an unprecedented speed. However, our knowledge on disease recovery is sparse and concerns about long-term pulmonary impairments are increasing. Causing a broad spectrum of symptoms, COVID-19 can manifest as acute respiratory distress syndrome (ARDS) in the most severely affected patients. Notably, pulmonary infection with Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), the causing agent of COVID-19, induces diffuse alveolar damage (DAD) followed by fibrotic remodeling and persistent reduced oxygenation in some patients. It is currently not known whether tissue scaring fully resolves or progresses to interstitial pulmonary fibrosis. The most aggressive form of pulmonary fibrosis is idiopathic pulmonary fibrosis (IPF). IPF is a fatal disease that progressively destroys alveolar architecture by uncontrolled fibroblast proliferation and the deposition of collagen and extracellular matrix (ECM) proteins. It is assumed that micro-injuries to the alveolar epithelium may be induced by inhalation of micro-particles, pathophysiological mechanical stress or viral infections, which can result in abnormal wound healing response. However, the exact underlying causes and molecular mechanisms of lung fibrosis are poorly understood due to the limited availability of clinically relevant models. Recently, the emergence of SARS-CoV-2 with the urgent need to investigate its pathogenesis and address drug options, has led to the broad application of in vivo and in vitro models to study lung diseases. In particular, advanced in vitro models including precision-cut lung slices (PCLS), lung organoids, 3D in vitro tissues and lung-on-chip (LOC) models have been successfully employed for drug screens. In order to gain a deeper understanding of SARS-CoV-2 infection and ultimately alveolar tissue regeneration, it will be crucial to optimize the available models for SARS-CoV-2 infection in multicellular systems that recapitulate tissue regeneration and fibrotic remodeling. Current evidence for SARS-CoV-2 mediated pulmonary fibrosis and a selection of classical and novel lung models will be discussed in this review.

Pulmonary function and radiological features 4 months after COVID-19: first results from the national prospective observational Swiss COVID-19 lung study

Background

The infectious coronavirus disease 2019 (COVID-19) pandemic is an ongoing global healthcare challenge. Up to one-third of hospitalised patients develop severe pulmonary complications and acute respiratory distress syndrome. Pulmonary outcomes following COVID-19 are unknown.

Methods

The Swiss COVID-19 lung study is a multicentre prospective cohort investigating pulmonary sequelae of COVID-19. We report on initial follow-up 4 months after mild/moderate or severe/critical COVID-19 according to the World Health Organization severity classification.

Results

113 COVID-19 survivors were included (mild/moderate n=47, severe/critical n=66). We confirmed several comorbidities as risk factors for severe/critical disease. Severe/critical disease was associated with impaired pulmonary function, i.e. diffusing capacity of the lung for carbon monoxide (D_LCO) % predicted, reduced 6-min walk distance (6MWD) and exercise-induced oxygen desaturation. After adjustment for potential confounding by age, sex and body mass index (BMI), patients after severe/critical COVID-19 had a D_LCO 20.9% pred (95% CI 12.4–29.4% pred, p=0.01) lower at follow-up. D_LCO % pred was the strongest independent factor associated with previous severe/critical disease when age, sex, BMI, 6MWD and minimal peripheral oxygen saturation at exercise were included in the multivariable model (adjusted odds ratio per 10% predicted 0.59, 95% CI 0. 37–0.87; p=0.01). Mosaic hypoattenuation on chest computed tomography at follow-up was significantly associated with previous severe/critical COVID-19 including adjustment for age and sex (adjusted OR 11.7, 95% CI 1.7–239; p=0.03).

Conclusions

4 months after severe acute respiratory syndrome coronavirus 2 infection, severe/critical COVID-19 was associated with significant functional and radiological abnormalities, potentially due to small-airway and lung parenchymal disease. A systematic follow-up for survivors needs to be evaluated to optimise care for patients recovering from COVID-19.

COVID-19 pulmonary sequelae are unknown. The Swiss COVID-19 lung study reports on initial follow-up findings. Severe or critical COVID-19 was associated with significant functional impairment and radiological abnormalities after 4 months.https://bit.ly/34sNVvi

Prognostic Implications of CT Feature Analysis in Patients with COVID-19: a Nationwide Cohort Study

BACKGROUND

Few studies have classified chest computed tomography (CT) findings of coronavirus disease 2019 (COVID-19) and analyzed their correlations with prognosis. The present study aimed to evaluate retrospectively the clinical and chest CT findings of COVID-19 and to analyze CT findings and determine their relationships with clinical severity.

METHODS

Chest CT and clinical features of 271 COVID-19 patients were assessed. The presence of CT findings and distribution of parenchymal abnormalities were evaluated, and CT patterns were classified as bronchopneumonia, organizing pneumonia (OP), or diffuse alveolar damage (DAD). Total extents were assessed using a visual scoring system and artificial intelligence software. Patients were allocated to two groups based on clinical outcomes, that is, to a severe group (requiring O₂ therapy or mechanical ventilation, n = 55) or a mild group (not requiring O₂ therapy or mechanical ventilation, n = 216). Clinical and CT features of these two groups were compared and univariate and multivariate logistic regression analyses were performed to identify independent prognostic factors.

RESULTS

Age, lymphocyte count, levels of C-reactive protein, and procalcitonin were significantly different in the two groups. Forty-five of the 271 patients had normal chest CT findings. The most common CT findings among the remaining 226 patients were ground-glass opacity (98%), followed by consolidation (53%). CT findings were classified as OP (93%), DAD (4%), or bronchopneumonia (3%) and all nine patients with DAD pattern were included in the severe group. Uivariate and multivariate analyses showed an elevated procalcitonin (odds ratio [OR], 2.521; 95% confidence interval [CI], 1.001-6.303, P = 0.048), and higher visual CT scores (OR, 1.137; 95% CI, 1.042-1.236; P = 0.003) or higher total extent by AI measurement (OR, 1.048; 95% CI, 1.020-1.076; P < 0.001) were significantly associated with a severe clinical course.

CONCLUSION

CT findings of COVID-19 pneumonia can be classified into OP, DAD, or bronchopneumonia patterns and all patients with DAD pattern were included in severe group. Elevated inflammatory markers and higher CT scores were found to be significant predictors of poor prognosis in patients with COVID-19 pneumonia.

Differential diagnosis between the coronavirus disease 2019 and Streptococcus pneumoniae pneumonia by thin-slice CT features

OBJECTIVE

The chest computed tomography (CT) features of coronavirus disease 2019 (COVID-19) and Streptococcus pneumoniae pneumonia (S. pneumoniae pneumonia) were compared to provide further evidence for the differential imaging diagnosis of patients with these two types of pneumonia.

METHODS

Clinical information and chest CT data of 149 COVID-19 patients between January 9, 2020 and March 15, 2020 and 97 patients with S. pneumoniae pneumonia between January 23, 2011 and March 18, 2020 in Zhongnan Hospital of Wuhan University were retrospectively analyzed. In addition, CT features were comparatively analyzed.

RESULTS

According to the chest CT images, the probability of lung segmental and lobar pneumonia in S. pneumoniae pneumonia was higher than that in COVID-19(P<0.001); the probabilities of ground-glass opacity (GGO), the "crazy paving" sign, and abnormally thickened interlobular septa in COVID-19 were higher than those in S. pneumoniae pneumonia(P = 0.005, P<0.001, P<0.001, respectively); and the probabilities of consolidation lesions, bronchial wall thickening, centrilobular nodules, and pleural effusion in S. pneumoniae pneumonia were higher than those in COVID-19 (P<0.001, P = 0.001, P = 0.003, P = 0.001, respectively).

CONCLUSION

The findings of GGO, the crazy paving sign, and abnormally thickened interlobular septa on chest CT were significantly higher in COVID-19 than S. pneumoniae pneumonia. The most important differential points on chest CT signs between COVID-19 and S. pneumoniae pneumonia were whether disease lesions were distributed in entire lung lobes and segments and whether the crazy paving sign, interlobular septal thickening, and consolidation lesions were found.

COVID-19 variant radiological findings with high lightening other coronavirus family (SARS and MERS) findings: radiological impact and findings spectrum of corona virus (COVID-19) with comparison to SARS and MERS

Background

Chest CT is remarkably considered as an imminent diagnostic tool and follow-up study in pulmonary changes in COVID-19 patients; being familiar to other coronavirus family CT findings, this improve our diagnostic experience and hence enhance our ability to early diagnose and combat the outbreak of COVID-19. The purpose is to investigate the wide spectrum of radiological pulmonary changes in COVID-19 patients and compare them to the variable CT findings reported in MERS and SARS.

Results

From March 15 to May 12, 2020, 50 patients in Cairo, Egypt, who have positive RT-PCR tests, were included in our study. MSCT of the chest was performed to all patients and processed in a separate work station. Two experienced radiologists assessed each study for the type and location of different pulmonary affection.

The most imminent radiological finding was patchy peripheral subpleural ground glass opacity found in 42 patients (84% of cases), followed by consolidation found in 30 patients (60% of cases) and ground glass and consolidation together found in 22 patients (44% of cases).

Unlike SARS, where initial chest imaging abnormalities are more frequently unilateral, COVID-19 is more likely to involve both lungs on initial imaging presented as bilateral peripheral subpleural scattered ground-glass opacities.

Pleural effusion is absent in COVID-19 patients while it is not rare in MERS and might be observed in 20–33% of affected individuals.

Conclusion

The imaging features of COVID-19 pneumonia are highly sensitive mainly in the outbreak pandemic.

The imaging features of SARS, MERS, and COVID-19 overlap, but differences still exist especially early in disease course.

A hypothesis for pathobiology and treatment of COVID-19: The centrality of ACE1/ACE2 imbalance

Angiotensin Converting Enzyme2 is the cell surface binding site for the coronavirus SARS-CoV-2, which causes COVID-19. We propose that an imbalance in the action of ACE1- and ACE2-derived peptides, thereby enhancing angiotensin II (Ang II) signalling is primary driver of COVID-19 pathobiology. ACE1/ACE2 imbalance occurs due to the binding of SARS-CoV-2 to ACE2, reducing ACE2-mediated conversion of Ang II to Ang peptides that counteract pathophysiological effects of ACE1-generated ANG II. This hypothesis suggests several approaches to treat COVID-19 by restoring ACE1/ACE2 balance: (a) AT receptor antagonists; (b) ACE1 inhibitors (ACEIs); (iii) agonists of receptors activated by ACE2-derived peptides (e.g. Ang (1-7), which activates MAS1); (d) recombinant human ACE2 or ACE2 peptides as decoys for the virus. Reducing ACE1/ACE2 imbalance is predicted to blunt COVID-19-associated morbidity and mortality, especially in vulnerable patients. Importantly, approved AT antagonists and ACEIs can be rapidly repurposed to test their efficacy in treating COVID-19. LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.

Respiratory follow-up of patients with COVID-19 pneumonia

The COVID-19 pandemic has led to an unprecedented surge in hospitalised patients with viral pneumonia. The most severely affected patients are older men, individuals of black and Asian minority ethnicity and those with comorbidities. COVID-19 is also associated with an increased risk of hypercoagulability and venous thromboembolism. The overwhelming majority of patients admitted to hospital have respiratory failure and while most are managed on general wards, a sizeable proportion require intensive care support. The long-term complications of COVID-19 pneumonia are starting to emerge but data from previous coronavirus outbreaks such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) suggest that some patients will experience long-term respiratory complications of the infection. With the pattern of thoracic imaging abnormalities and growing clinical experience, it is envisaged that interstitial lung disease and pulmonary vascular disease are likely to be the most important respiratory complications. There is a need for a unified pathway for the respiratory follow-up of patients with COVID-19 balancing the delivery of high-quality clinical care with stretched National Health Service (NHS) resources. In this guidance document, we provide a suggested structure for the respiratory follow-up of patients with clinicoradiological confirmation of COVID-19 pneumonia. We define two separate algorithms integrating disease severity, likelihood of long-term respiratory complications and functional capacity on discharge. To mitigate NHS pressures, virtual solutions have been embedded within the pathway as has safety netting of patients whose clinical trajectory deviates from the pathway. For all patients, we suggest a holistic package of care to address breathlessness, anxiety, oxygen requirement, palliative care and rehabilitation.

A hypothesis for pathobiology and treatment of COVID-19: The centrality of ACE1/ACE2 imbalance

Angiotensin Converting Enzyme2 is the cell surface binding site for the coronavirus SARS-CoV-2, which causes COVID-19. We propose that an imbalance in the action of ACE1- and ACE2-derived peptides, thereby enhancing angiotensin II (Ang II) signalling is primary driver of COVID-19 pathobiology. ACE1/ACE2 imbalance occurs due to the binding of SARS-CoV-2 to ACE2, reducing ACE2-mediated conversion of Ang II to Ang peptides that counteract pathophysiological effects of ACE1-generated ANG II. This hypothesis suggests several approaches to treat COVID-19 by restoring ACE1/ACE2 balance: (a) AT receptor antagonists; (b) ACE1 inhibitors (ACEIs); (iii) agonists of receptors activated by ACE2-derived peptides (e.g. Ang (1-7), which activates MAS1); (d) recombinant human ACE2 or ACE2 peptides as decoys for the virus. Reducing ACE1/ACE2 imbalance is predicted to blunt COVID-19-associated morbidity and mortality, especially in vulnerable patients. Importantly, approved AT antagonists and ACEIs can be rapidly repurposed to test their efficacy in treating COVID-19. LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.

Hypothesis: The potential therapeutic role of nicorandil in COVID-19

At present, there is yet no specific antiviral treatment or immunization against the newly identified human severe acute respiratory syndrome virus (SARS-CoV2) that results in a rapidly progressive pandemic coronavirus disease 2019 (COVID-19). We believe in a crucial need for a clinical strategy to counteract this viral pandemic based on the known pathogenesis throughout the disease course. Evidence suggests that exaggerated patient's inflammatory response and oxidative stress are likely to aggravate the disease pathology. The resulting endothelial dysfunction further induces fibrosis and coagulopathy. These disturbances can generate severe acute respiratory distress syndrome (ARDS) that can progress into respiratory and circulatory failure. Nicorandil is an anti-anginal vasodilator drug acts by increasing nitric oxide bioavailability and opening of the KATP channel. Recently, nicorandil has been recognized to possess multiple protective effects against tissue injury. Here, we address a possible modulatory role of nicorandil against COVID-19 pathogenesis. We hypothesise nicorandil would be an effective form of adjuvant therapy against COVID-19.

Pleural effusion as an isolated finding in COVID-19 infection

Common radiological findings of COVID -19 infection include bilateral ground-glass opacities in lower lobes with a peripheral distribution. Pleural effusion is considered a rare manifestation of COVID -19 infection. We present a 52 years old patient with a three-week history of right-sided pleuritic chest pain, fever, and dyspnea. Laboratory investigations revealed high C-reactive protein and ferritin levels and a positive COVID-polymerase chain reaction (PCR) from a nasopharyngeal swab. Chest X-ray and Computed tomography (CT) identified a moderate right-sided pleural effusion, which was exudative with mixed cellularity and high Lactate dehydrogenase (LDH). Histopathology of thoracoscopic pleural biopsy didn't reveal granulomas, malignancy, or any microbiological growth. We postulate that having ruled out any other cause the effusion was likely related to the Covid-19 infection. Our case highlights that COVID-19 can present with isolated pleural effusions, therefore it should be kept as an etiology of effusions especially if other possible causes have been ruled out.

Imaging differences between coronavirus disease 2019, severe acute respiratory syndrome, and Middle East respiratory syndrome

Since the outbreak of Coronavirus Disease-19 (COVID-19) infection in December 2019 in Wuhan, the capital Hubei province, central of China, more than 4 million people have contracted the virus worldwide. Despite the imposed precautions, coronavirus disease-19 is rapidly spreading with human-to-human transmission resulting in more than 290,000 death as of May 13, 2020 according to World Health Organization (WHO). The aim of this study was to revise the characteristic imaging features of Sever Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) during their outbreak, and to compare them with that of COVID-19, to familiarize radiologists with the imaging spectrum of corona-virus syndromes. This study will help in more understanding and characterisation of COVID-19 to support the global efforts in combating its worldwide outbreak.

Pneumothorax in patients with prior or current COVID-19 pneumonia

As the number of COVID-19 cases emerge, new complications associated with the disease are recognized. We present three cases of spontaneous pneumothorax in patients with COVID-19. They show that a pneumothorax can occur during different phases of disease, in patients without a pulmonary disease history and is not necessarily associated to positive pressure ventilation or severity of COVID-19. Although the exact causative mechanisms remain unknown, this observation might imply that extensive alveolar destruction due to COVID-19 may lead to bulla formation resulting in subsequent pneumothorax.

COVID-19 - A Brief Review of Radiology Testing

I

COVID-19: TESTINGA

Laboratory Testing - CDC Guidelines

Analysis of 2019 novel coronavirus infection and clinical characteristics of outpatients: An epidemiological study from a fever clinic in Wuhan, China

Background

Since the outbreak of 2019 novel coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS‐CoV‐2]) pneumonia, thousands of patients with fever or cough were flocked into fever clinic of designated hospitals in Wuhan, China. To date, no data have ever been reported to reflect the prevalence of coronavirus disease 2019 (COVID‐19) among these outpatients. Moreover, it is almost unknown to discriminate COVID‐19 and nucleic acid negative patients based on clinical features in the fever clinics.

Methods

The infectious status of SARS‐CoV‐2 was estimated among the outpatients. The epidemiological and clinical characteristics were compared between COVID‐19 and nucleic acid negative patients.

Results

The nucleic acid positive rate for SARS‐CoV‐2 in the outpatients from our fever clinic was 67·1%, while the majority of patients with COVID‐19 were mild cases. The predominant initial symptom in those patients with COVID‐19 was fever (78.2%), followed by cough (15.6%). Very significantly lower number of eosinophils was characterized in patients with COVID‐19 as compared with that of nucleic acid negative patients. More importantly, the proportion of subjects with eosinophil counts lower than normal levels in patients with COVID‐19 was much higher than that of nucleic acid negative patients. Fever combined with bilateral ground‐glass opacities in computed tomography imaging and eosinophil count below the normal level are probably a valuable indicator of COVID‐19 infection in those outpatients.

Conclusions

Those findings may provide critical information for the regions, such as Europe and United States that are facing the same situation as Wuhan experienced, and could be valuable to prevent those nucleic acid negative patients from misdiagnosis before antibody testing.

This article may provide critical information for the regions that are facing epidemic, and could be valuable to prevent those nucleic acid negative patients from misdiagnosis before antibody testing.

Combating the Coronavirus Pandemic: Early Detection, Medical Treatment, and a Concerted Effort by the Global Community

The World Health Organization (WHO) has declared the outbreak of 2019 novel coronavirus, known as 2019-nCoV, a pandemic, as the coronavirus has now infected over 2.6 million people globally and caused more than 185,000 fatalities as of April 23, 2020. Coronavirus disease 2019 (COVID-19) causes a respiratory illness with symptoms such as dry cough, fever, sudden loss of smell, and, in more severe cases, difficulty breathing. To date, there is no specific vaccine or treatment proven effective against this viral disease. Early and accurate diagnosis of COVID-19 is thus critical to curbing its spread and improving health outcomes. Reverse transcription-polymerase chain reaction (RT-PCR) is commonly used to detect the presence of COVID-19. Other techniques, such as recombinase polymerase amplification (RPA), loop-mediated isothermal amplification (LAMP), clustered regularly interspaced short palindromic repeats (CRISPR), and microfluidics, have allowed better disease diagnosis. Here, as part of the effort to expand screening capacity, we review advances and challenges in the rapid detection of COVID-19 by targeting nucleic acids, antigens, or antibodies. We also summarize potential treatments and vaccines against COVID-19 and discuss ongoing clinical trials of interventions to reduce viral progression.

Urgent reconsideration of lung edema as a preventable outcome in COVID-19: inhibition of TRPV4 represents a promising and feasible approach

Lethality of coronavirus disease (COVID-19) during the 2020 pandemic, currently still in the exponentially accelerating phase in most countries, is critically driven by disruption of the alveolo-capillary barrier of the lung, leading to lung edema as a direct consequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We argue for inhibition of the transient receptor potential vanilloid 4 (TRPV4) calcium-permeable ion channel as a strategy to address this issue, based on the rationale that TRPV4 inhibition is protective in various preclinical models of lung edema and that TRPV4 hyperactivation potently damages the alveolo-capillary barrier, with lethal outcome. We believe that TRPV4 inhibition has a powerful prospect at protecting this vital barrier in COVID-19 patients, even to rescue a damaged barrier. A clinical trial using a selective TRPV4 inhibitor demonstrated a benign safety profile in healthy volunteers and in patients suffering from cardiogenic lung edema. We argue for expeditious clinical testing of this inhibitor in COVID-19 patients with respiratory malfunction and at risk for lung edema. Perplexingly, among the currently pursued therapeutic strategies against COVID-19, none is designed to directly protect the alveolo-capillary barrier. Successful protection of the alveolo-capillary barrier will not only reduce COVID-19 lethality but will also preempt a distressing healthcare scenario with insufficient capacity to provide ventilator-assisted respiration.

Implications for forensic death investigations from first Swiss post-mortem CT in a case of non-hospital treatment with COVID-19

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3D Visualisation of lung pathology allows to better estimate the distribution of aerated, poorly aerated and non-aerated lung regions

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Forensic COVID-19 autopsy apparently showing a different (higher) degree of pathology than hospital autopsy reports compared to SARS-COV-2, but on par with SARS.

Case details: A case of a 50-year old HIV-positive man is presented, with focus on visualization of post-mortem computed tomography (PMCT) of the lungs, in comparison to a forensic control case. He had been found dead at home, a day after his nasopharyngeal swab had returned positive for SARS-COV-2, three days after the sample had been taken as an outpatient, over five weeks after first exhibiting possible symptoms. 3D-visualization was performed by visually discriminating correlates for aerated, poorly aerated and non-aerated lung regions. The visual side-by-side comparison with a control case shows the deterioration beyond any ”normal” post-mortem finding, however. The PMCT findings in the lungs resemble those of patients with acute respiratory distress syndrome (ARDS), while histologically identified inflammation also shows, in part binuclear, lymphocytes. In addition, acute liver dystrophy and acute tubular necrosis in the kidneys were found. Except coronary artery atherosclerosis, there appeared to be no remarkable pathology of the heart.

Comment: With the pandemic impact of SARS-COV-2, a range of issues unfolds, also for medicolegal investigations into deaths, as we report the first Swiss case with post-mortem CT where death had occurred due to a SARS-COV-2 infection, with features of a severe acute respiratory distress syndrome, as an outpatient. As this pandemic from the view of risk assessment does constitute a black swan, underestimated fat tails as technical reason should be addressed by also analyzing apparent extreme single observations. This case of an outpatient (without hospital or intensive-care treatment) shows a pulmonary progression beyond the typical findings of COVID-19, to a non-specific picture of ARDS, where histologically, in part binuclear lymphocytes were remarked. What appeared to be an initially slow progression with final rapid escalation raises the question whether nasopharyngeal swabs alone or added pulmonary CT might be better for screening high-risk patients. The reported symptoms and relatively late medical consultation in this case appeared to contrast with the extensive pathology, raising the question whether any search for super-spreaders should not just focus on asymptomatic but under-reported symptomatic patients, and whether their prolonged circulation in everyday life would justify measures such as for example more extensive face mask policies. As post-mortem testing for SARS-COV-2 may not be available for every case, PMCT may provide sensitive testing for lung changes related to COVID-19. In order to allow for more precise medicolegal investigations in the context of COVID-19, however, any more specific extra tests may have to be financed by stakeholders in epidemiology, infectious disease or policy.

Chest CT Findings in Patients With Coronavirus Disease 2019 and Its Relationship With Clinical Features

OBJECTIVES

The aim of this study was to investigate the chest computed tomography (CT) findings in patients with confirmed coronavirus disease 2019 (COVID-19) and to evaluate its relationship with clinical features.

MATERIALS AND METHODS

Study sample consisted of 80 patients diagnosed as COVID-19 from January to February 2020. The chest CT images and clinical data were reviewed, and the relationship between them was analyzed.

RESULTS

Totally, 80 patients diagnosed with COVID-19 were included. With regards to the clinical manifestations, 58 (73%) of the 80 patients had cough, and 61 (76%) of the 80 patients had high temperature levels. The most frequent CT abnormalities observed were ground glass opacity (73/80 cases, 91%), consolidation (50/80 cases, 63%), and interlobular septal thickening (47/80, 59%). Most of the lesions were multiple, with an average of 12 ± 6 lung segments involved. The most common involved lung segments were the dorsal segment of the right lower lobe (69/80, 86%), the posterior basal segment of the right lower lobe (68/80, 85%), the lateral basal segment of the right lower lobe (64/80, 80%), the dorsal segment of the left lower lobe (61/80, 76%), and the posterior basal segment of the left lower lobe (65/80, 81%). The average pulmonary inflammation index value was (34% ± 20%) for all the patients. Correlation analysis showed that the pulmonary inflammation index value was significantly correlated with the values of lymphocyte count, monocyte count, C-reactive protein, procalcitonin, days from illness onset, and body temperature (P < 0.05).

CONCLUSIONS

The common chest CT findings of COVID-19 are multiple ground glass opacity, consolidation, and interlobular septal thickening in both lungs, which are mostly distributed under the pleura. There are significant correlations between the degree of pulmonary inflammation and the main clinical symptoms and laboratory results. Computed tomography plays an important role in the diagnosis and evaluation of this emerging global health emergency.

Diagnostic value and key features of computed tomography in Coronavirus Disease 2019

On 31 December 2019, a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, Hubei province, China, and caused the outbreak of the Coronavirus Disease 2019 (COVID-19). To date, computed tomography (CT) findings have been recommended as major evidence for the clinical diagnosis of COVID-19 in Hubei, China. This review focuses on the imaging characteristics and changes throughout the disease course in patients with COVID-19 in order to provide some help for clinicians. Typical CT findings included bilateral ground-glass opacity, pulmonary consolidation, and prominent distribution in the posterior and peripheral parts of the lungs. This review also provides a comparison between COVID-19 and other diseases that have similar CT findings. Since most patients with COVID-19 infection share typical imaging features, radiological examinations have an irreplaceable role in screening, diagnosis and monitoring treatment effects in clinical practice.

CT imaging changes of corona virus disease 2019(COVID-19): a multi-center study in Southwest China

BACKGROUND

Since the first case of a coronavirus disease 2019 (COVID-19) infection pneumonia was detected in Wuhan, China, a series of confirmed cases of the COVID-19 were found in Southwest China. The aim of this study was to describe the imaging manifestations of hospitalized patients with confirmed COVID-19 infection in southwest China.

METHODS

In this retrospective study, data were collected from 131 patients with confirmed coronavirus disease 2019 (COVID-19) from 3 Chinese hospitals. Their common clinical manifestations, as well as characteristics and evolvement features of chest CT images, were analyzed.

RESULTS

A total of 100 (76%) patients had a history of close contact with people living in Wuhan, Hubei. The clinical manifestations of COVID-19 included cough, fever. Most of the lesions identified in chest CT images were multiple lesions of bilateral lungs, lesions were more localized in the peripheral lung, 109 (83%) patients had more than two lobes involved, 20 (15%) patients presented with patchy ground glass opacities, patchy ground glass opacities and consolidation of lesions co-existing in 61 (47%) cases. Complications such as pleural thickening, hydrothorax, pericardial effusion, and enlarged mediastinal lymph nodes were detected but only in rare cases. For the follow-up chest CT examinations (91 cases), We found 66 (73%) cases changed very quickly, with an average of 3.5 days, 25 cases (27%) presented absorbed lesions, progression was observed in 41 cases (46%), 25 (27%) cases showed no significant changes.

CONCLUSION

Chest CT plays an important role in diagnosing COVID-19. The imaging pattern of multifocal peripheral ground glass or mixed consolidation is highly suspicious of COVID-19, that can quickly change over a short period of time.

COVID-19: urgent reconsideration of lung edema as a preventable outcome Inhibition of TRPV4 as a promising and feasible approach

Lethality of Covid-19 during the 2020 pandemic, currently in the exponentially-accelerating phase in most countries, is critically driven by disruption of the alveolo-capillary barrier of the lung, leading to lung edema as a direct consequence of SARS-CoV-2 infection. We argue for inhibition of the TRPV4 calcium-permeable ion channel as a strategy to address this issue, based on the rationale that TRPV4 inhibition is protective in various preclinical models of lung edema, and that TRPV4 hyperactivation potently damages the alveolo-capillary barrier, with lethal outcome. We believe that TRPV4 inhibition has a powerful prospect at protecting this vital barrier in Covid-19 patients, even to rescue a damaged barrier. A clinical trial using a selective TRPV4 inhibitor demonstrated a benign safety profile in healthy volunteers and in patients suffering from cardiogenic lung edema. We argue for expeditious clinical testing of this inhibitor in Covid-19 patients with respiratory malfunction and at risk for lung edema. We note that among the currently pursued therapeutic strategies against Covid-19, none is designed to directly protect the alveolo-capillary barrier. Successful protection of the alveolo-capillary barrier will not only reduce Covid-19 lethality but will pre-empt a catastrophic scenario in healthcare with insufficient capacity to provide ventilator-assisted respiration.

Radiology Perspective of Coronavirus Disease 2019 (COVID-19): Lessons From Severe Acute Respiratory Syndrome and Middle East Respiratory Syndrome

OBJECTIVE. Since the outbreak of the novel coronavirus pulmonary illness coronavirus disease 2019 (COVID-19) in China, more than 79,000 people have contracted the virus worldwide. The virus is rapidly spreading with human-to-human transmission despite imposed precautions. Because similar pulmonary syndromes have been reported from other strains of the coronavirus family, our aim is to review the lessons from imaging studies obtained during severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) outbreaks. CONCLUSION. The review of experiences with the MERS and SARS outbreaks will help us better understand the role of the radiologist in combating the outbreak of COVID-19. The known imaging manifestations of the novel coronavirus and the possible unknowns will also be discussed.

Health Care-Associated Infections and the Radiology Department

Health care-associated infections (HCAIs) are a significant concern for both health care workers (HCWs) and patients. They are a major contributing factor of disease in industrialized countries, and are responsible for significant morbidity, mortality, and a direct annual financial loss of $6-7 billion in North America alone. They are an increasingly challenging health issue due to multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci among others, along with an increasing number of susceptible patients. Over the last three decades, the risk of HCAIs has increased in the radiology department (RD) in part because of an increased number of patients visiting the department and an increase in the utilization of imaging modalities. In this review, we will discuss how patients and staff can be exposed to HCAIs in the RD, including contaminated inanimate surfaces, radiology equipment, and associated medical devices. As the role of medical imaging has extended from primarily diagnosis to include more interventions, the implementation and development of standardized infection minimization protocols and infection control procedures are vital in the RD, particularly in interventional radiology. With globalisation and the rapid movement of people regionally, nationally, and globally, there is greater risk of exposure to contagious diseases such as Ebola, especially if infected patients are undiagnosed when they travel. For effective infection control, advanced training and education of HCWs in the RD is essential. The purpose of this article is to provide an overview of HCAIs as related to activities of the RD. We will discuss the following major topics including the variety of HCAIs commonly encountered, the role of the RD in HCAIs, transmission of infections to patients and HCWs in the RD, standard infection prevention measures, and the management of susceptible/infected patients in the RD. We shall also examine the role of, and the preparedness of, HCWs, including RD technologists and interventional radiologists, who may be exposed to undiagnosed, yet infected patients. We shall conclude with a brief discussion of the role of further research related to HCAIs. Learning Objectives After the completion of this review article, the readers will • Understand the exposure and role of radiology department in health care-associated infections, • Know the causes/modes/transmission of infections in radiology department, • Be conscious of standard disinfection protocols, • Be aware of current and future strategies required for the effective control of health care-associated infection in the radiology department. This is a CME article and provides the equivalent of 2 hours of continuing education that may be applied to your professional development credit system. A 10-question multiple-choice quiz follows this reading. Please note that no formalized credit (category A) is available from CAMRT.

The role of epidermal growth factor receptor (EGFR) signaling in SARS coronavirus-induced pulmonary fibrosis

Many survivors of the 2003 outbreak of severe acute respiratory syndrome (SARS) developed residual pulmonary fibrosis with increased severity seen in older patients. Autopsies of patients that died from SARS also showed fibrosis to varying extents. Pulmonary fibrosis can be occasionally seen as a consequence to several respiratory viral infections but is much more common after a SARS coronavirus (SARS-CoV) infection. Given the threat of future outbreaks of severe coronavirus disease, including Middle East respiratory syndrome (MERS), it is important to understand the mechanisms responsible for pulmonary fibrosis, so as to support the development of therapeutic countermeasures and mitigate sequelae of infection. In this article, we summarize pulmonary fibrotic changes observed after a SARS-CoV infection, discuss the extent to which other respiratory viruses induce fibrosis, describe available animal models to study the development of SARS-CoV induced fibrosis and review evidence that pulmonary fibrosis is caused by a hyperactive host response to lung injury mediated by epidermal growth factor receptor (EGFR) signaling. We summarize work from our group and others indicating that inhibiting EGFR signaling may prevent an excessive fibrotic response to SARS-CoV and other respiratory viral infections and propose directions for future research.

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Patients who survived SARS coronavirus infection often developed pulmonary fibrosis.

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Mouse models of SARS-CoV infection recapitulate fibrotic lesions seen in humans.

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Epidermal growth factor receptor (EGFR) may modulate the wound healing response to SARS-CoV.

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The EGFR pathway is a prime target for therapeutic interventions to reduce fibrosis after respiratory virus infection.

Thin-Section Computed Tomography Manifestations During Convalescence and Long-Term Follow-Up of Patients with Severe Acute Respiratory Syndrome (SARS)

Background

SARS is not only an acute disease, but also leads to long-term impaired lung diffusing capacity in some survivors. However, there is a paucity of data regarding long-term CT findings in survivors after SARS. The aim of this study was to assess the changes in lung function and lung thin-section computed tomography (CT) features in patients recovering from severe acute respiratory syndrome (SARS), especially the dynamic changes in ground-glass opacity (GGO).

Material/Methods

Clinical and radiological data from 11 patients with SARS were collected. The serial follow-up thin-section CTs were evaluated at 3, 6, and 84 months after SARS presentation. The distribution and predominant thin-section CT findings of lesions were evaluated.

Results

The extent of the lesions on the CT scans of the 11 patients decreased at 6 and 84 months compared to 3 months. The number of segments involved on 84-month follow-up CTs was less than those at 6 months (P<0.05). The predominant thin-section CT manifestation at 84 months (intralobular and interlobular septal thickening) was different than that at 6 months, at which GGO was predominant.

Conclusions

During convalescence after SARS, GGO and intralobular and interlobular septal thickening were the main thin-section CT manifestation. Intralobular and interlobular septal thickening predominated over GGO at 84 months.

Pulmonary sequelae in a patient recovered from swine flu

The pandemic of swine flu (H1N1) influenza spread to involve the whole world rapidly. Many patients manifested a mild clinical illness but some developed pneumonia and respiratory failure. High mortality was observed in patients with severe disease. Among survivors, studies are limited. Ground-glass opacities on a high-resolution computerized tomography scan and reduced diffusion capacity were noted after 3 months in a study. But long-term complications in patients with swine flu pneumonia have not been studied well. We are presenting an unusual case of swine flu pneumonia who developed interstitial lung disease after recovery.

Evaluation of monkeypox disease progression by molecular imaging

Infection of nonhuman primates (NHPs) with monkeypox virus (MPXV) is currently being developed as an animal model of variola infection in humans. We used positron emission tomography and computed tomography (PET/CT) to identify inflammatory patterns as predictors for the outcome of MPXV disease in NHPs. Two NHPs were sublethally inoculated by the intravenous (IV) or intrabronchial (IB) routes and imaged sequentially using fluorine-18 fluorodeoxyglucose ((18)FDG) uptake as a nonspecific marker of inflammation/immune activation. Inflammation was observed in the lungs of IB-infected NHPs, and bilobular involvement was associated with morbidity. Lymphadenopathy and immune activation in the axillary lymph nodes were evident in IV- and IB-infected NHPs. Interestingly, the surviving NHPs had significant (18)FDG uptake in the axillary lymph nodes at the time of MPXV challenge with no clinical signs of illness, suggesting an association between preexisting immune activation and survival. Molecular imaging identified patterns of inflammation/immune activation that may allow risk assessment of monkeypox disease.